Thank you for contacting extension with this question.
I'd be interested to know what kind of oak trees you are observing dying. And if there are any related factors going on... are these yard trees?
To answer your question, there is nothing specific or epidemic going on in Culpeper again the Oaks. The past several years, however, have seen significant oak mortality and frankly we don't have very defined reasons why in many cases.
It's often a combination of factors going back several years.
Here are a few reputable resources that may be of interest:
and this one from the Virginia Department of Forestry (page 6): www.dof.virginia.gov/print/health/review/health-review-2006-11.pdf
Otherwise, if you have yard trees that are in decline and you want to do something about, I recommend contacting a certified arborist.
If you have significant mortality in a forest setting and would like to explore if a salvage harvest of those trees is an option, contact a consulting forester.
I hope this helps.
Feel free to contact me again if I can be of assistance.